The present invention relates to a header intended for installation into culverts, water conduits, and watercourses for the purpose of restricting and controlling the flow of storm water in ditches, swales and other watercourses.
During rainstorm events, and as a result of snow-melt, runoff water is directed into swales ditches and other conduits including storm sewers, and conducted in a largely uncontrolled manner to watercourses, lakes and rivers. In severe storms this can result large volumes of water moving at high velocities which can, in many instances, erode watercourses, and river banks, and damage culverts, roads and driveways, as well as carry contaminants from the watershed with deleterious results to the environment.
In undeveloped areas, interception and infiltration often retains much of the initial rainfall, but in developed areas, where the surface is largely impervious, or in situations where the ground has reached maximum saturation, or is frozen, the rapid rate of runoff can have extreme results, degrading water quality and damaging sewer infrastructure.
A system or device which will capture and detain high volumes of initial runoff for later release at a controlled rate into the drainage system, will delay and reduce water flow volume and velocity, protecting the infrastructure and the natural watercourses from physical and ecological damage.
The present invention provides for this control in a simple and effective manner, and functions without moving parts and little if any maintenance requirement.
In accordance with the present invention, a control header for culverts comprises a head-wall having an opening on the downstream face which is sized to match the diameter of the culvert, attached wing-walls, extending away from the head-wall on opposite sides thereof, and an adjustable inlet control device for regulating the flow through the opening into the culvert. Preferably the wing-walls are hinged to the head-wall, permitting the header to adapt to a variety of applications.
The above structure prevents erosion and damage to culverts and driveways overhead, and adjacent to the ditch or swale served by the culvert, as well as downstream watercourses of all types. The adjustable inlet is provided with screening means to facilitate the removal of trash and floatable solids by limiting their passage through drainage systems and into watercourses. Moderation of the velocity and volume of water flowing in the ditch reduces erosion in receiving watercourses thereby reducing erosion and undermining of banks. First flush water is detained which allows precipitation of suspended solids and improved water quality. Extended detention of storm-water aids in groundwater recharge and augmenting downstream base flow. Erosion and heaving of road and driveway crossings is achieved by controlling piping and saturation of bedding materials. Safety of individuals and animals is enhanced by providing means for their escape or removal at each header location. The esthetic appearance of an integrated head-wall and wing-wall assembly creates a clean image.
When used in a linked system, with applicant""s headers installed in series at multiple culvert locations, the combined upstream storage capacity can provide both water quality and quantity benefits and minimize requirements for xe2x80x9cend of pipexe2x80x9d pond facilities that are expensive and generally require the use of otherwise utilizable land.
In accordance with the present invention, the header can be manufactured from non-corrosive plastic or ferrous materials, and is compact in form to facilitate low cost packaging and shipping. Designed for assembly in the field, flexibility is provided since the header can be easily adjusted to suit a variety of installation requirements, various construction materials and situations. By means of knock outs the xe2x80x9clow flow rate of the header can be adjusted to detain large volumes of rainwater, providing slow release into the system at a controlled rate.
The header includes an overflow weir which provides for the exact and specific control of the water levels retained at each culvert location, while allowing for passage of large volumes of water once the upstream storage area has reached maximum volume, or in extreme runoff events.
The header is so designed that a single stock-keeping unit can be used for and installed in a multiplicity of culvert sizes, thus simplifying inventory control and reducing inventory units and management.